Is there any way to get these things clean to like-new condition again? I've already tried Bar Keeper's Friend with both a blue Scotch-Brite sponge and a 3M stainless steel scrub pad, but there's still a fair amount of burnt on gunk remaining. I'm only using the pan and basket to cook vegetables on medium-low to medium heat. I know there are harsher chemicals out there but I don't want to damage the pan.